The purpose of this proposal is to disseminate polymer microelectrode arrays and promote their integrated into neuroscience research practice. Such polymer neural interfaces are mechanically compliant to promote stability of the device-tissue interface and versatile in that both surface and penetrating electrode arrays can be produced with the same technology. To accomplish their dissemination and integration, a resource will be created that offers the ability to customize electrode designs for their applications that are compatible with other recording and stimulation technologies and imaging technologies. The state-of-the-art polymer probes with high channel count will be made available to select users through project proposals selected with the input of a steering committee and to the broader community as prototypes on shared multi-project processing runs. Importantly, devices produced through user engagement will be functionally tested and ready to implant. The multi-project wafer processing runs will allow for small numbers of custom devices from multiple users to be produced on a single mask set which will allow users to debug and perform design adjustments and allow the resource to efficiently utilize wafer real estate. The resource also offers a testing service to validate electrode arrays made by external users. The successful in vivo implementation of interface technologies is dependent of their repeatable construction and reliable performance; these may be difficult to attain in small batch prototypes and even in commercially produced devices because of lack of testing capabilities or expertise. Device testing services will ensure rigor, reproducibility, and transparency for the benefit of the user community. The testing approach will be comprehensive, beginning at the materials level and progressing to the interface, interconnections, and packaging. Testing will include techniques that examine surface properties, material properties, mechanical performance, electrical and electrochemical performance, and lifetime testing. As needed, testing will be tailored for each project as dictated by its end use requirements. The testing methodologies will be rigorously documented and also disseminated. To facilitate adoption of technologies by users, the resource will offer onsite training on how to implement electrode arrays in vivo in rat. The resource seeks to enable BRAIN Initiative investigators and the broader community to achieve large scale recordings that will impact fundamental neuroscience research and next generation neuroprosthetic platforms for the treatment of multiple neurological disorders and conditions.